Development and Identification of a Closed-Loop Model of the Cardiovascular System Including the Atria

Abstract

The atria play an important role in cardiac function. The introduction of two chambers representing the atria in an existing model of the cardiovascular system could provide useful information. A previously validated cardiovascular system model is modified to include the atria, whose behaviour is modelled in an original way. An a-wave pressure independent of the volume is introduced to make the model more realistic. This is one of the ten new parameters that are introduced in the atrial model. Six of these parameters are identified with an extension of the previously existing parameter identification method. A method to infer important atrial pressure characteristics from the ventricular pressure waveform is also developed. Identification of the model parameters with and without atria are performed using data sets from a pulmonary embolism pig trial. The error is bigger in the model containing the atria, but remains of the order of measurement errors. The model with atria provides useful information about these two new compartments, without requiring the need for new measurements. This work is a useful improvement of the already existing model and identification methods as it now allows characterization of atrial function.